Composition for coating



Patented Dec. 30, 1924.

coMPosITIoN ron COATING.

THEODORE 'FRANQOIS TESSE, OF PARIS, FRANCE.

FoDrawing. Application filed January 30, 1918, Serial No, 214,521. Renewed Decembei' 11, 1 920. I I

" serial 110. 430,045.

T all 1.0715227.- z't may conccmz:

Be it known that l, THEODORE FnANgois "lEssE. acitizen of the Republic of Switzerland, and residing at. 69 Avenue des Ternes,

5 Paris, France. have invented certain new proof and smooth at first, after a very short period lose their waterproof quality and their property of producing andgmaintaining tension, and moreover it has been found by experience that in warm climates such plain coatings become brittle in many cases. I In order to improve such products and also to obtain colored effects, it has been Y proposed to cover the wings impregnated with cellulose acetate with fatty varnish in linseed oil or with a coat of varnish paint. The: results obtained in the campaign of 191445 in France have shown that such varnishes cannot meet with the requirements necessitated by the tremendous strain to which the supporting surfaces of aeroplanes are subjected.

- Moreover, these products do not withstand the effects of'bad Weather or variations in 40 temperature,v and soon produce a slackness of the cloth. They are also extremely sensitive to mineral spirit, motor'oils and pro longed action of rain. Hence the problem of a satisfactory coating was still to be solved and the present invention has for its object the PIOVlSlOIl ofa coating composition meeting with all requirements and without the disadvantages previously experienced.

I have found that the solution of the problem is not in using a simple solution alone in a solvent of low boiling point, but

a composition which while containing cellulose acetate of a certain character in a solvent of low boiling point, contain also high percentage of other components found nec essary in order'that the finished product will meet the required conditions. V I have further found that a highly'suit able coating is one composed of a succession of three layers. the composition ofthe I F intermediate one of which forms the subject matter of the present case. I have found it to be'necessary to use a' o5 cellulose acetate possessing a high degree of polymerization, such a cellulose acetate giving a solution of high viscosity. C'oatin'gs having as a base such a .cellulose acetate are stable and-resistant, whereas an 7 acetate of slight degree of polymerization yields a solution of low viscosity and the coating produced therefrom is not. resistant and soon becomes dry and brittle.

The addition of the other products in this invention is based on the fact, not previ- 'lfiou'sly considered, of the important function e which can be played by the combination of certain plasticityingagentshaving high boiling points in the presence'of an inert material. I i

The plasticifyin'g agents having high boiling pointsparticularly suitable are:

1. The bodies of the methyl-propyl-phenol series whose boiling points are aboutv 200 C., or above, and which are mostly liquid at'ordinary temperature; for instance, carvacrol (boiling point 236 C.) andalso. its isomerfcarvol (boiling point 225 (1.).

2. The esters of mono-hydric phenols having unsaturated lateral chains, as well as their isomersuand their methylic derivatives, and especially e-u genol (boiling point about 247.5 O.) and isoeugenol (boiling point 260 (1). One or more of the substances of classes 1 and 2 maybe'used, and eugenol .has given especially good results.

Such class of bodies are employed in the composition inorder to supply the necessary plasticity and elasticity. The substances Y mentioned in. the last two paragraphs exercise a further important function,in that they also preserve the cellulose ester from disintegration under the action of sunlight and weather. These materials can accordbe referred to as imparting. added ingly durabilityto', the cellulose esters, since they prevent decomposition thereof by the elements (sunshine, rain, fog, etc.).

3. In addition to the bodies. above men-' 'tioned, certain lQQdiQE are advantageously 11c employed togive some degree of softness and suppleness for example triacetin (boiling point about 258 (3.). Y

. 4. A body of a fourth class (in most cases) has to be employed in combination with bodies of the second or with the second and third classes. One of its functions is to avoid the precipitation of the cellulose ester (shown by the formation v to the supple intermediate coating a stretching which balances any undesirable soften-- intermediate layer according to may be precipitation ing effect due to the relatively high percentage of substance of high boiling points 'necessarily'used. Zinc oxid may be used as an'example of this class of inert material or if it is desired to produce a colored coating, organic or mineral coloring matter maybe employed. Another advantage of this inert material is the'reduction of the inflammability of the finished coating."

The following is an example of the mannor in which the coating composition for. the

- prepared:

First, an 8% solution of cellulose acetate in acetone or methyl acetate is prepared.

The proportion of cellulose acetatemay vary according to the density and the nature of the inert material that is employed. 100 kgs.,of this solution are mixed with em 5 kgs. of very fine and very light, and preferably uncompressed zinc oxid and the whole is then passed through a suitable grinding machine (e. g. a paint mill) until the zinc oxid has been converted into an'impalpable powder. After the grinding operation the resulting paste has incorporated with it the following:-2 to 3 kgs. of carvol or one of the other products above ,mentioned, preferably eugenol, and 1 to 2 kgs. of triacetin. For the purpose'of facilitating the formation of the skin produced by the application of the coating composition, acetoacetic ether is added tothe composition, and .1f"des1red a small quantity of pyridine or other liquid-having the properties stated,

and having a boilingpoint not appreciably, below 100 C. These additions produce a more progressivedrying of the coating composition owing tothe progressive eliminatiQnof the volatile substances.

(B) To the substances of thechamQWF- istics mentioned in classes 1, 2, 3 and 4 above, I also preferably add, either with or without a pigment, a metallic powder such as aluminum, such powder being composed not of granular, spherical or rounded or ground particles, but being a powder, the separate particles of which are of a flakelike or flat sheet-like character. This flake like form of aluminum powder may conveniently be manufactured by known methods. for instance from aluminum powder which may be. of a somewhat coarse granular form, by passing such powder between smooth rolls, under considerable pressure, whereby the particles thereof will be fiattened out, into the form desired.

When this flaky form of metallic powder is mixed with. acomposition as above described and the resulting composition is spread out on. the surface to be coated, the flakes each settle into a substantially horizontal position, overlapping each other, whereby upon the evaporation of the low boiling point solvent, they form a laminar membrane, Ora-sort 'of a structural frame work composed of the overlapping flakes, which greatly increases the strength of the intermediate layer, and hence (of the entire coating. The coating thus produced hence be comes much more firm and strong which could not be produced by the use of a powder compound of rounded granules or particles i Thereis another important function pro duced by the use of the flake-like form of metallic powder, namely that it reflects substantially all ofthelight rays and in this respect is superior toother forms of material. I

In many cases it is necessary to produce a colored composition, for instance, forca-mouflage where different colors to represent forests, rocks, water, etc., are required' In such cases an inert coloring matter must be employed, but even with such inert coloring matter, the" specified form of aluminum powderis highly advantageous, so that we have in fact in the coating composition two inert materials, one being the pigment and the other being the metallic powder.

\Vhile I have particularly specified the employment of aluminum, as this metal has especial utility in connection'with the coating of aeroplane wings-on account of its u l I I color, etc., and on account of its malleabiht-y is easy to work into the desired flake-form.

the invention is not limited'thereto, but embraces also Various othermetals'and alloys. (examples being copper, bronze, 'etc.). A

"In connection with the improvement described I have above referred to the use of pigments. These may be white or colored,

shouldlbe bornein mind that the pigment will be one which does not deleteriouslyrcthecoating.

act upon the other constituents of the coating composition. Also place of the pigments, specifically mentioned, various? o1;-

' ganicor-mineral'coloring matter may be used,

Both the pigments and th'e'aluminun'i powder serve to reduce the inflammability of The complete coating composition for producing the intermediate layer, isgivenfor the purpose of illustration but theinvention,

' is not limited to-the details thereof of the finely powdered pigment, such as-lead chromate, white zine oxid,Turnbu-lPs-;:-blue First, an 8%-solution of-eellulose acetate in'acetone 'or methyl acetateor'other suitable volatile solvent is prepared. Into'100 kgs. of such a solution ane mixed 2 to 3 kgs.

or burnt sienna, etc., together with '2 kgs. of the fine flake-form aluminum. der and 1 to 2 kgs. of triacetin and 2' to 3' kgs. of eugenol and 2 to 3 kgsof benzylic alcohol. The-composition is then thoroughly mixed, in any ordinary mixing machine, for a sufiicient time to produce a thorough incorporation of the ingredients The finished coating com-posed of the three layers above referred to, is'unaflfected by variations of temperature or by the action of prolonged rain. It is impermeable,

wate'rproofand smooth and being smooth, it presents less resistance to the air passing over the surface of the wing with a conse-. 'quent increase in speed of the aeroplane. I

'It can be easily cleaned by washing with soap and water and can. also be rapidly and readily repaired. It is unaffected by the action of light and possesses the-necessary elasticity. 1 f q he present'application is in part a continuation of matter disclosed in my copending applications, as follows 2-.-

,- (claiming the processes of 'Serial No. 71,201, filed and Serial No. 123,640, filed October &, 1916, coating herein January 10, 1916,

described) Referenceis also made to mycopending application 221,089, filed Mar. -7, 1918,, in

which claims were presented on covering the fabrics of aeroplanes with the dope (coat ing composition) as claimed herein, and to the product produced.

What I claim is:

1. A coating composition comprising a solution is a volatile solvent, of a cellulose ester ofa fattv acid, a liquid having a boiling point of net materially-below 200 C. for

imparting plasticity and elasticity, a liquid having a boiling'point not'appreciably below 100 C. capable of preventing the precipitation of the cellulose ester during the evaporation of the. solvent, together with metallic flake-form aluminumpowder.

'ble material eapableojf neu 2. A coating composition comprisin a? solution in a volatile solvent, of a cellu ose ester of a fatty acid, a materialcapable of blending with said ester, having a boiling point of not materially below 200C. and

capable of imparting plasticity and elasiticity, a liquid material which is capable of imparting softness, another liquid having a boiling point not apprec ably below-100 (1., capable of preventingv the precipitation of the'cellulose ester, during the evap'orati'O IIjOi thB solvent, togethe ithjfan insolusive softness produc tioned additions.

3. 'A' coating composi solution in methyl acetate; merized cellulose acetate abQVe men- :highlypoly-I 1" 'enol, triaceti ne, and benzylic alcohol,-t get er' with a pig- ,ment and flaky aluminiinftpowder.

aliiing exces comprising a 4. A coating, compositioncompr'is'ing for imparting plasticity and elasticity, a-

liquidli a-ving a boiling point not appreciably below 100 C. and capable of preventing the precipitation of the cellulose ester, and tri-. acetin, together with an inert solid material for increasing the resistance of the coating.

6. A coating composition comprising a solution, in-a volatile'solvent, of a cellulose ing point of notvmaterially below 200 C.

i ester of a fatty acid, a liquid having a boilfor imparting plasticity and elasticity, 'another liquid which is capable of imparting softness, a third liquid having a boiling 'point not appreciably below 100 0., and, capable of preventingthe precipitation of the cellulose ester during the evaporation of the solvent, together with an inert solid material for "increasing the resistance of the coating. y

7. A coating composition comprising a solution inmethyl-acetate of a highly polymeri'zed-cellulose acetate, eugenol, triacetin, gand benzylic alcohol, together withia i ment. I

solution in a readily'volatile solvent, of'a cellulose ester of a fatty acid, a liquid having a boiling point of not materially-below 200 C. for impartingplasticity and elasticity, another liqmd having a boiling point not 8'. A- coating composition comprising a [evaporating solvent permits gradual deposi-' effect. i g 11. A composition for treating aeroplane" 10. A composition for treating aeroplane and similar fabrics comprising a relatively non-inflammable cellulose ester, a volatilesolvent and added materiahhaving a boiling point approximately 245 C., whereby added durability is im-arted to the cellulosedeposit, and also a-slowly evaporating solvent having a boiling point in the neigh- 20 borhood 0f160 0., whereby the slowly tion of the cellulose ester without whitening and similar fabricscomprising a relatively non-inflammable cellulose ester, a. volatile solvent and added material having a boiling point between approximately 200 and 260 (1., wherebyadded durability is imparted to the cellulose -esterdeposit, said added material being soluble in the usua solvents of cellulose esters.

'12. A composition for treating aeroplane and similar fabrics comprising a relatively non-inflammable cellulose ester, a volatile solvent and added material soluble in saidsolvent having a boiling point between apdurability is imparted to the cellulose ester .deposit, .and'also a slowly evaporating solvent capable of preventing precipitation of "the cellulose ester during the evaporation of the volatile solvent, whereby the slowly evaporating solvent permits gradual deposition of the cellulose ester without whitening effect.

. 13. A composition for treating aeroplane and similar fabrics comprising a relatively non-inflammable cellulose ester, a tension regulating ingredient in such'proportion to said cellulose ester as to reduce the tautening efiectof the cellulose ester upon-the fab-- ric, and a volatile solvent for said ingredients.

14. A com osition for treating aeropla e and slmilar. abrics comprising a relative y non-inflammable cellulose ester, .a tension regulating ingredient in such proportion to the cellulose ester as to reduce the t'auten-v and having a boiling point not substantially below 150 C. I.

15. A composition for treating aeroplane and similar fabrics comprising a relatively non-inflammable cellulose Lester, a volatile solvent and added material soluble therein and capable of giving plasticity and elasticity, and having a boiling point be ween 225 and 260 (1., whereby added dura 't is impartedito the coating. i

16. A composition for treating aeroplane and similar fabrics comprising arelatively non-inflammable cellulose ester, a volatile solvent and added material soluble therein and capable of increasing the plasticity and elasticity of the cellulose ester, and having a boiling point between 225 and 260 (3., whereby added durability is imparted to the coating.

17. A composition for treating aeroplane and similar fabrics comprising a relatively non-inflammable cellulose ester, a volatile solvent and added material capable of blending with said ester to'i'mpart plasticity and elasticity, and having a boiling point between 225 and 260 0., whereby added durability'is imparted to'the cellulose ester deposit, and also a slowly evaporating solvent having a boiling point not substantially below 150 0., whereby the slowly evaporating solvent permits gradual deposition of the cellulose ester without precipitation.

18. A cellulose ester dope of the kind set forth containing a cellulose ester, asmaller amount pf a plasticising solvent for said cellulose ester, the boilin point of such solvent being above 200 5., together with a volatile solvent. and triacetin, for the purpose specified. i

i 19, A composition for .treating aeroplane andsim'ilar fabrics comprising arelatively non-infiammable cellulose ester, a tension regulating ingredient in-such proportion to said cellulose ester as to reduce the tautening effect of the cellulose ester upon the fabric, and a volatile solvent for said ingredients, and a substance adapted to prevent precipitation of the cellulose ester during the evaporation of the. volatile solvent.

In testimony whereof I afiix my signature. THEODORE FRANooIs TESSE. 

